Question

当我第一次下载列表时，一切正常，但滚动后第二个和第三个元素之间的边距增加（列表大小为10个元素）。我发现这个代码可以做到，但我不明白为什么以及如何解决它（我需要在最后一个元素的末尾有边距）：

我的适配器：

 @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

        //...

        // margin for the last element
        if (position == getItemCount() - 1) {
            Resources r = activity.getResources();
            float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, MARGIN_END_LAS_ELEMENT, r.getDisplayMetrics());
            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                    LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
            layoutParams.setMargins(0, 0, (int) px, 0);
            holder.itemView.setLayoutParams(layoutParams);
        }

       //...

    }

的xml：

 <android.support.v7.widget.RecyclerView
        android:id="@+id/rvHoriz"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

item xml layout：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/llRoot"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    tools:ignore="ContentDescription">

    <RelativeLayout
        android:layout_width="@dimen/video_longrid_film_image_w"
        android:layout_height="@dimen/video_longrid_film_image_h"
        android:layout_marginLeft="@dimen/video_longrid_film_image_margin"
        android:layout_marginStart="@dimen/video_longrid_film_image_margin"
        android:layout_marginTop="@dimen/video_longrid_film_image_margin_top">

        <ImageView
            android:id="@+id/ivPoster"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:src="@drawable/ic_longrid_film_placeholder"/>

        <ImageView
            android:layout_width="@dimen/video_longrid_fav_icon_size"
            android:layout_height="@dimen/video_longrid_fav_icon_size"
            android:id="@+id/ivFavIcon"
            android:src="@drawable/favorite"
            android:layout_alignParentTop="true"
            android:layout_alignParentRight="true"
            android:layout_alignParentEnd="true"
            android:visibility="gone"/>

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/ivParent"
            android:layout_centerInParent="true"
            android:src="@drawable/lock_poster"
            android:visibility="gone"/>



    </RelativeLayout>


    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/video_longrid_film_image_margin_bottom"
        android:layout_marginLeft="@dimen/video_longrid_film_image_margin"
        android:layout_marginStart="@dimen/video_longrid_film_image_margin"
        android:ellipsize="marquee"
        android:includeFontPadding="false"
        android:focusable="true"
        android:focusableInTouchMode="true"
        android:marqueeRepeatLimit="0"
        android:maxLines="1"
        android:textColor="@color/video_longrid_title_color"
        android:textSize="@dimen/video_longrid_film_text"/>

    <TextView
        android:id="@+id/tvGenre"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:includeFontPadding="false"
        android:layout_marginTop="@dimen/video_longrid_film_title_margin_bottom"
        android:layout_marginLeft="@dimen/video_longrid_film_image_margin"
        android:layout_marginStart="@dimen/video_longrid_film_image_margin"
        android:ellipsize="marquee"
        android:focusable="true"
        android:focusableInTouchMode="true"
        android:marqueeRepeatLimit="0"
        android:maxLines="1"
        android:textColor="@color/video_longrid_genre_color"
        android:textSize="@dimen/video_longrid_film_text"/>


</LinearLayout>

Answer 1

您需要在条件语句中添加 else ，如下所示：

// Set margin for the last element
if (position == getItemCount() - 1) {
    Resources r = activity.getResources();
    float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, MARGIN_END_LAS_ELEMENT, r.getDisplayMetrics());
    LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    layoutParams.setMargins(0, 0, (int) px, 0);
    holder.itemView.setLayoutParams(layoutParams);
} else {
    // Set the margin for non-last element here
    ...
}

这是因为滚动时会重复使用视图，因此对视图所做的任何更改在重复使用时都会显示，除非您重置它。

在RecycerView

1 个答案: